The present invention relates to the mixing of fluid dispersions and more specifically to apparatus and methods for mixing paint disposed in a container having either a cylindrical or a square shape.
As is well known, solids in fluid dispersions, such as paint, tend to settle in a downward direction through the force of gravity. Fluid dispersions disposed in containers for commercial sale are typically mixed in the containers before they are used by the purchasers. Many fluid dispersions can be facilely mixed in a container by manually shaking the container. Other fluid dispersions, however, such as paint, are more difficult to manually mix in a container and, thus, are often mixed in the container using a machine that shakes, rotates, vibrates or otherwise moves the container.
A variety of different types of mixing machines are known for mixing fluid dispersions disposed in containers. Examples of conventional mixing machines include those disclosed in U.S. Pat. No. 3,542,344 to Oberhauser, U.S. Pat. No. 4,235,553 to Gall, and U.S. Pat. No. 4,497,581 to Miller, all of which are hereby incorporated by reference. These and most other conventional mixing machines can only accommodate cylindrical containers. Such mixing machines cannot properly accommodate generally square containers. It has been proposed, however, to package fluid dispersions, such as paint, in generally square containers. An example of one such container is disclosed in U.S. patent application Ser. No. US2001/0025865A1 to Bravo et al. Accordingly, there is a need in the art for an apparatus and method for mixing fluid dispersions disposed in generally square containers as well as cylindrical containers. The present invention is directed to such an apparatus and method.